Analysis of cardiac arrhythmias during dobutamine pharmacologic stress testing in nuclear cardiology as related to the presence or absence of baseline arrhythmias

Background. Intravenous dobutamine is an acceptable pharmacologic stress agent for evaluation of myocardial ischemia, but it has the undesirable side effect of precipitating cardiac arrhythmias. All patients are susceptible to the arrhythmogenic potential of dobutamine. However, the presence of a baseline arrhythmia creates additional concern about proceeding with a pharmacologic dobutamine stress test. The purpose of this study was to evaluate cardiac arrhythmias during dobutamine stress as they relate to the presence or absence of baseline arrhythmias in patients undergoing radionuclide myocardial perfusion imaging. Methods and Results. Data from 486 consecutive dobutamine stress tests in nuclear cardiology were reviewed retrospectively. Baseline and stress electrocardiographic monitoring and 12-lead electrocardiograms were used for classification of arrhythmias. For patients without baseline arrhythmias, the estimated probability of having nonsustained ventricular tachycardia with dobutamine stress was 4.0% (16 of 403), as compared with 15.7% (13 of 83) for patients with baseline arrhythmias ( p < 0.001). Three of the 403 patients (0.7%) and 2 of the 83 patients (2.4%) had their study terminated because of ventricular tachycardia ( p > 0.05). Conclusions. The probability of having nonsustained ventricular tachycardia with dobutamine stress testing was significantly greater in patients who had baseline arrhythmias than in those who had no arrhythmias at baseline. Although termination of the study because of ventricular tachycardia was not statistically significant between these two groups, patients with baseline cardiac arrhythmias should be considered at higher risk for the development of nonsustained ventricular tachycardia during dobutamine stress testing than patients who have no baseline arrhythmia.